transition metals

pink [Co(H2O)6]2+ + 4Cl- forms what

blue [CoCl4]2- + 6H2O

colour change due to change in coordination number

what is formed when yellow [Co(NH3)6]2+ is oxidised?

brown [Co(NH3)6]3+ +e-

colour change as oxidation state changes

what is formed when pink [Co(H2O)6]2+ + 6 NH3?

brown [Co(NH3)6]2+ + 6H2O

colour change as ligand changed

contact process?

2SO2 + O2 → 2SO3

V2O5 acting as a heterogeneous catalyst in the contact process?

• SO2 + V2O5 → SO3 + V2O4

• 2V2O4 + O2 → 2V2O5

what is the manufacture of methanol catalysed by?

Cr2O3

CO + 2H2 → CH3OH

what is the haber process catalysed by?

Fe

N2 + 3H2 → 2NH3

how can catalysts become poisoned

impurities

may lose their efficiency + have to be replaced → costly

why cant lead petrol be used in cars w catalytic converters?

lead strongly adsorbs to catalyst

reaction of S2O8^2- and I- and what is it catalysed by?

Fe2+

S2O8^2- + 2I- → 2SO4^-2 + I2

why is reaction of S2O8^2- and I- slow?

between two (-) ions so AE high, and catalyst required to provide alternate pathway and lower it

how is a molecule able to act as a homogeneous catalyst?

if it has an Ecell between the Ecell’s of both the reactants

will reduce the one with a more positive Ecell, and oxidise the one with the more negative one

S2O8^2- half equation?

S2O8^2- + 2e- → 2SO4^2-

I- half equation?

I2 + 2e- → 2I-

Fe2+ half equation?

Fe3+ + e- → Fe2+

catalysed route of reaction between S2O8^2- and I-?

• S2O8^2- + 2Fe2+ → 2SO4^2- + 2Fe3+

• 2I- + 2Fe3+ → 2Fe2+ + I2

reaction can occur in any order so Fe3+ could act as catalyst also

what autocatalyses the reaction w/ C2O4^2- and MnO4^-

Mn2+ ions

C2O4^2- with MnO4^- equation?

2MnO4- + 5C2O4- + 16H+ → 2Mn2+ + 10CO2 + 8H2O

C2O4^2- with MnO4^- catalysed alternative route?

• 4Mn2+ + MnO4- + 8H+ → 5Mn3+ + 4H2O

• 2Mn3+ + C2O4^2- → 2Mn2+ + 2CO2

how can rate of reaction be monitored? eg with MnO4- ions

• can remove samples and quench at set times + titrate to find conc of reactant being used up

• can measure intensity of colour as it changes throughout the reaction via a colorimeter; intensity of purple. better as does not disrupt the reaction + finds conc. quicker

why are the chloride ions in [Cu(H2O)₆]Cl₂ not considered to be ligands?

Cl- isn’t donating a lone pair to Cu2+, so isn’t forming a coordinate bond with it

the Cl₂ shouldn't be included in reactions eg. addition of NH3, NaOH etc

in ligand substitutions where the shape of molecule remains the same, why is the value of enthalpy change close to zero?

same number and type of bond being broken and made

test for ammonium ions?

add warm NaOH + warm

NH4+ + OH- → NH3 + H2O

test with red litmus paper → turns blue

haem?

Fe3+ complex w/ a multidentate ligand with a O=O [oxyhaemoglobin] which binds reversibly so can be transported and then replaced w/ H2O [deoxyhaemoglobin]

toxic if CO replaces as the product is very stable and irreversible w/ out treatment so prevents Fe2+ from transporting O2

how does cisplatin anti-cancer drug work?

Cl- replaced w/ H2O

H2O replaced guanine [N bonded]

other Cl- replaced w/ guanine

bonds prevent DNA strands from separating

toxic but benefits>risks

what is delta E?

energy dif between ground and excited state, corresponds to WL of light

(J) delta E=hV(freq in s^-1 or hz)

V= c/Y (wave speed/wave length)

measurement conversions?